1. Stating the problem: We need to find the resistance $R$ of a 2000 m long iron wire, given its resistivity $\rho = 1.0 \times 10^{-7} \ \Omega m$ and its circumference $C = 0.02 \ m$. 2. Recall the resistance formula for a wire: $$ R = \rho \frac{L}{A} $$ where $L$ is the length of the wire and $A$ is the cross-sectional area. 3. Calculate the cross-sectional radius from the circumference: The circumference $C$ of a circle is given by $$ C = 2 \pi r $$ Solving for radius $r$: $$ r = \frac{C}{2\pi} = \frac{0.02}{2 \times 3.1416} = 0.0031831 \ m $$ 4. Calculate the cross-sectional area $A$: $$ A = \pi r^2 = 3.1416 \times (0.0031831)^2 = 3.1831 \times 10^{-5} \ m^2 $$ 5. Substitute all known values into the resistance formula: $$ R = 1.0 \times 10^{-7} \times \frac{2000}{3.1831 \times 10^{-5}} $$ 6. Compute the resistance: $$ R = 1.0 \times 10^{-7} \times 6.2819 \times 10^{7} = 6.2819 \ \Omega $$ Final answer: $$ R \approx 6.28 \ \Omega $$